"Unique manuscripts have been conserved for centuries in Timbuktu, a scholarly city of 333 saints, where practically every household is a heritage site, a library," he said.

"I think there are serious risks to those manuscripts."

Mali has been in turmoil since a band of low-ranking army officers overthrew the government in a coup on March 22.

The officers said president Amadou Toumani Toure had failed to stand up to the Tuareg insurgency.

The power vacuum played into the hands of the insurgents who captured key towns in the vast arid north virtually unopposed.

'Frankly I'm afraid'

Timbuktu is home to nearly 100,000 ancient manuscripts, some dating to the 12th century, preserved in family homes and private libraries under the care of religious scholars.

At its height in the 1500s, the city, a Niger River port at the edge of the Sahara, was the key intersection for salt traders travelling from the north and gold traders from the south.

It was also a renowned centre of Islamic scholarship, with manuscripts written in Arabic and Fulani by scholars of the ancient Mali empire, covering a range of subjects including Islam, history, astronomy, music, botany, genealogy and anatomy.

Mr Bocoum says the manuscripts could be illegally sold or destroyed by the "new arrivals", who reportedly include Al Qaeda in the Islamic Maghreb, the north African branch of Al Qaeda.

Unique manuscripts have been conserved for centuries in Timbuktu, a scholarly city of 333 saints, where practically every household is a heritage site...I think there are serious risks to those manuscripts.

Institut Fondamental d'Afrique Noirse head Hamady Bocoum

"These manuscripts have survived through the ages thanks to a secular order, in an area of trade where all the region's peoples intersect. With the arrival of the Islamists, that secular order is broken, that culture is in danger," he said.

United Nations cultural agency UNESCO also issued a plea on Tuesday to protect the city's history.

"Timbuktu's outstanding earthen architectural wonders that are the great mosques of Djingareyber, Sankore and Sidi Yahia must be safeguarded," UNESCO director-general Irina Bokova said.

She called the city "essential to the preservation of the identity of the people of Mali and of our universal heritage".

UNESCO added Timbuktu to its World Heritage List in 1988 in recognition of its status as a legendary trade hub and its history stretching back to the 5th century.

The owner of one of the city's private libraries said he fears for his collection.

"I really don't know at the moment what's going to become of my manuscripts," he said.